Projection arrangement for projecting an image onto a projection surface

ABSTRACT

In a projection arrangement for projecting an image onto a projection surface, there are provided a light source ( 26 ), a control unit ( 25 ), a light modulator ( 10 ), which is controllable by said control unit ( 25 ) in order to generate an image on the basis of predetermined image data, an optical device ( 11 ), arranged following said light modulator, for projecting said image onto the projection surface ( 34 ), a film stage ( 2 ) for holding a positive image recorded on a carrier medium, projection optics ( 3 ), arranged following the film stage ( 2 ) when projecting the positive image, and a control device ( 6 ), allowing either to direct light from the light source ( 26 ) to the light modulator ( 10 ) or to illuminate a positive image, which is held by the film stage ( 2 ), with said light. Thus, a projection arrangement is provided which can project both positive images and images generated on the basis of predetermined data onto a projection surface ( 34 ).

The invention relates to a projection arrangement for projecting animage onto a projection surface.

Such a projection arrangement is, for example, a projector forprojecting a motion picture, which comprises a light source, amechanical film stage and a projection lens. The light source emits alight ray bundle which illuminates positive images on a film guidedtransversely to the light propagation direction of the light ray bundle.The illuminated positive images are projected onto a screen by theprojection lens. During operation, the film is unwound from a film reelor a film disk on one side of the film stage, guided across said filmstage, and wound up on the other side of the film stage on another filmreel or another film disk. The film is guided discontinuously across thefilm stage such that the film is moved past a picture gate on the filmstage and stopped, 24 times per second, each individual image beingilluminated twice. At the same time, the control signals for the theatersound system are also sampled. Such projector only allows conventionalmovies to be projected. A projection of movies, which are present onlyas digital and/or analog data and for the projection of which the imagesto be projected have to be generated first on the basis of said data, isnot possible.

However, such movies have a number of advantages over conventionalmovies. Thus, it is possible to distribute such movies faster and moreeasily than conventional movies, because either a data carrier (e.g. aDVD), on which the data are recorded, may be shipped or the data may betransmitted directly via data lines, and it is no longer necessary toship heavy film reels. Further, the quality of image and sound remainsunchanged even after frequent screenings, while the quality ofconventional movies may deteriorate with each screening. For theprojection of such movies, which are present only as data, there areprojection devices which comprise light modulators for imaging, saidlight modulators allowing to generate the image according to said imagedata. As light modulators, for example, LCD modules or tilting mirrormatrices (DMD chips) are used. If the projector for projectingconventional movies is replaced by such projection arrangement, thiswill result in a high cost of acquisition, since an entire projectionarrangement needs to be acquired. Further, such projection arrangementwill no longer allow conventional movies to be screened.

EP 0,961,502 A2 describes a movie projector for projecting digitalmovies. This movie projector consists of the light source of aconventional movie projector for projecting conventional movies and of adigital front module, which is fixed to the housing of the light sourceinstead of the film stage. This allows to convert a conventional movieprojector to a digital projector and to save costs, because the lightsource of the conventional projector can be used for said digitalprojector. However, said digital projector still has the disadvantagethat it is no longer possible to project a conventional movie. Also,said conversion is labor-extensive, because the film stage needs to bedismounted completely.

Now, the invention is intended to remedy this and to improve theaforementioned projection arrangement such that the projectionarrangement is suitable for the projection of both a positive imagerecorded on a carrier medium and of an image to be generated on thebasis of predetermined image data. Moreover, a supplementary module foruse with such projection arrangement is to be proposed.

According to the invention, this problem is solved by a projectionarrangement for projecting an image onto a projection surface, saidarrangement comprising a light source, a control unit, a lightmodulator, which is controllable by said control unit in order togenerate an image on the basis of digital and/or analog image data, anoptical device, arranged following said light modulator, for projectingsaid image onto the projection surface, a film stage for holding apositive image recorded on a carrier medium, projection optics, arrangedfollowing the film stage during projection, and a control device,allowing either to direct light from the light source to the lightmodulator or to illuminate a positive image, which is held by the filmstage, with said light.

In an advantageous embodiment of the projection arrangement according tothe invention, the control device comprises an optical deflectingelement (e.g. a mirror), which may direct the light from the lightsource to the light modulator. Said optical deflecting element may bemoved back and forth between a first position, in which it is arrangedin the optical path of the light emitted by the light source, betweenthe light source and the projection optics, and in which it deflectssaid light, and a second position, in which it is not arranged in saidoptical path and, consequently, does not deflect the light to the lightmodulator. Preferably, said optical deflecting element is disposedbetween the light source and the film stage. Thus, there is no need todismount the film stage and, at the same time, a compact configurationof the projection arrangement according to the invention may be realizedas well.

Preferably, the projection arrangement according to the invention may befurther embodied such that the light modulator is movable into anoptical path extending from the light source via the film stage to theprojection surface. Thus, the optical path of the projection arrangementremains unchanged, so that a simple construction of the projectionarrangement may be realized.

The projection arrangement according to the invention may be furtherembodied such that the control device comprises an optical path switcharranged in the optical path between the light source and the projectionoptics, or arranged following the film stage. Preferably, said opticalpath switch may be an electronically switchable element, so that nomechanical movement of components is required for switching the opticalpath.

The light modulator, the optical device and the control device arepreferably provided as an attachable module. On the one hand, thisallows the use, as the light source for the light modulator, of thelight source of a conventional projector for projecting positive images.On the other hand, the mechanical film stage and the associatedprojection optics of the conventional projector can remain as they are,so that conventional movies may continue to be projected. Further, theconversion of an already existing, conventional projector to theprojection arrangement according to the invention is easily possible,since, due to the control device, the mechanical film stage of theconventional projector need not be dismounted.

Preferably, the projection arrangement according to the invention may befurther embodied such that the control device comprises a device bywhich the light source is movable from a first position, in which thelight is incident on the light modulator, to a second position, in whichthe light is incident on the film stage. Alternatively, the controldevice may comprise a device by which the light modulator is movabletogether with the film stage from a first position, in which the lightis incident on the light modulator, to a second position, in which thelight is incident on the film stage. Said device of the control deviceensures that the images generated on the basis of the predeterminedimage data, or conventional positive images, may be projected.

Particularly advantageously, the projection arrangement according to theinvention may be further embodied such that a splitting device isprovided, which splits the light from the light source into differentcolor components, and that the light modulator comprises severallight-modulating units, each of which modulates one of said colorcomponents. This configuration allows to obtain light outputs which meetthe brightness requirements of movie theaters.

In a further advantageous embodiment of the projection arrangementaccording to the invention, combining optics are provided which combinethe light emitted by light-modulating units to form one single lightbundle and guide it to the optical device. This advantageously allowsthe modulated light of different colors to be imaged onto the screen bymeans of an optical device.

Preferably, the projection arrangement according to the invention isfurther embodied such that the light modulator comprises an LCDmodule—which may be in the form of a transmission or reflection module—aGLV module, or a tilting mirror matrix. Thus, a high-quality image maybe generated.

In a further advantageous embodiment, the projection optics and theoptical device of the projection arrangement according to the inventionare comprised in one single projection device. Thus, it is possible toprovide a projection arrangement requiring only one projection device,which allows to save costs.

The projection arrangement according to the invention may advantageouslybe further embodied such that a memory for storing data is provided.Said memory may be a digital memory, e.g. a computer hard disk, or mayalso be an analog memory, such as a conventional video tape. Byproviding such memory, the entire movie may be stored in the projectionarrangement, so that there is no need for high transmission capacitiesof a connection with an external movie memory.

In another advantageous embodiment of the invention, the projectionarrangement according to the invention comprises an interface forreceiving data. Said interface may be, for example, a DVD drive. It mayalso be an interface for a computer network, such as the internet. Thisallows new movies to be transmitted to the projection arrangement asfast as possible and to be projected after or even during transmission.

In a further advantageous embodiment of the invention, a display deviceand an image recording device are provided, said image recording devicebeing able to record the image projected onto the projection surface andto represent it on the display device. When the image recording devicerecords the film projected onto the projection surface and reproduces iton the display device, it is possible to control the performance fromoutside the auditorium. Thus, for example, failure of the projectionlamp or of the auditorium lighting may be diagnosed at once.

Further, the projection arrangement according to the invention maycomprise several projection units, each comprising a light source; afilm stage, arranged following said light source, for holding a positiveimage recorded on a carrier medium; projection optics, arrangedfollowing the film stage when projecting the positive image; and a firstcoupling member; said projection arrangement further comprising acontrol unit; a supplementary module comprising a light modulator whichis controllable by the control unit in order to generate an image on thebasis of predetermined image data; an optical device, arranged followingthe light modulator, for projecting said image onto the projectionsurface; and a second coupling member, wherein the supplementary modulemay be coupled to the projection units via said coupling members, andwherein said supplementary module further comprises a control device,allowing either to direct light from the light source of that projectionunit to which the supplementary module is coupled, to the lightmodulator or to illuminate a positive image, which is held by the filmstage of said projection unit, with said light. This projectionarrangement advantageously allows to provide only one supplementarymodule for several projection units and to couple said supplementarymodule to the corresponding projection unit, as required.

The supplementary module according to the invention for use in aprojection arrangement as described above comprises a control unit, alight modulator, which is controllable by said control device in orderto generate an image on the basis of predetermined image data, anoptical device, arranged following the light modulator, for projectingsaid image onto a projection surface, and a control unit, which device,when the supplementary module is in a condition coupled to a projectorcomprising a light source and a film stage, arranged following saidlight source, for holding a positive image recorded on a carrier medium,allows either to direct light from the light source to the lightmodulator or to illuminate a positive image, which is held by the filmstage, with said light. This supplementary module allows easy and fastretrofit of a conventional projector, so that it may project either apositive image recorded on a carrier medium or an image generated on thebasis of predetermined image data, as required.

A more detailed description of the invention, compared with a prior artexample, shall be given below basically by way of example and in view ofthe drawings, wherein:

FIG. 1 shows a schematic top view of a projection arrangement accordingto the invention;

FIG. 2 shows a top view of a light modulator according to an embodiment;

FIG. 3 shows a block diagram of the projection arrangement according tothe invention;

FIG. 4 shows a top view of the light modulator according to a furtherembodiment;

FIG. 5 shows a side view of the light modulator shown in FIG. 4;

FIGS. 6 and 7 show schematic views explaining an alternative embodimentof the deflecting unit;

FIG. 8 shows a schematic view explaining an alternative embodiment ofthe deflecting unit;

FIG. 9 shows a schematic view explaining an alternative embodiment ofthe deflecting unit;

FIGS. 10 and 11 show schematic views explaining an alternativeembodiment of the deflecting unit;

FIGS. 12 and 13 show schematic views explaining an alternativeembodiment of a light modulator; and

FIG. 14 shows a schematic top view of a conventional movie projector.

FIG. 15 schematically depicts an attachable module in accordance withthe present invention.

FIG. 16 schematically depicts a supplementary module in accordance withthe present invention.

FIG. 17 schematically depicts a moving device for moving the film stageand image modulator simultaneously.

FIG. 18 schematically depicts a moving device for moving a light sourcein accordance with the present invention; and

FIG. 19 schematically depicts an additional embodiment of the presentinvention.

For a better understanding of the projection arrangement according tothe invention, a brief description shall be given, with reference toFIG. 14, of the basic structure of a conventional projector forprojecting positive images or positive films. Such conventionalprojector contains a lamp housing 1, a mechanical film stage 2 and aprojection lens 3. In the lamp housing 1, a light source (not shown) isarranged, which emits a light ray bundle 4 transilluminating a positiveimage on a film 5 held on the mechanical film stage 2, which film isguided transversely to the light propagation direction of the light raybundle 4. The illuminated positive image is projected onto a projectionsurface (not shown) by means of the projection lens 3.

FIG. 1 shows a schematic top view of the projection arrangementaccording to the invention. Like the conventional projector shown inFIG. 14, the projection arrangement comprises a lamp housing 1, whereina light source (e.g. a xenon lamp), not shown, is arranged, a mechanicalfilm stage 2 and a projection lens 3. In addition, the projectionarrangement according to the invention includes a deflecting unit 6 andan image generating module 7. The deflecting unit 6 comprises a firstdeflecting mirror 8, which is mounted on a carriage, not shown, which ismovable perpendicular to the light propagation direction of the lightray bundle 4 by a motor and a worm gear. In the condition of theprojection arrangement according to the invention shown in FIG. 1, thefirst deflecting mirror 8 is arranged in the optical path between thelamp housing 1 and the mechanical film stage 2 in such a manner that thelight ray bundle 4 from the light source is deflected substantiallyperpendicular to the light propagation direction from the lamp housing 1to the mechanical film stage 2. The first deflecting mirror 8 may bemoved out of the optical path between the lamp housing 1 and themechanical film stage 2 using the carriage, not shown, so that the lightray bundle 4 is not deflected, as shown in FIG. 1, but illuminates afilm guided on the mechanical film stage 2. In this condition, astandard movie may be projected. However, in the condition shown in FIG.1, the first deflecting mirror 8 is arranged in the optical path betweenthe lamp housing 1 and the mechanical film stage 2, as shown in FIG. 1,using said carriage. The light ray bundle 4 deflected by the firstdeflecting mirror 8 is incident on a second deflecting mirror 9 of thedeflecting unit 6 and is deflected by said second deflecting mirror 9 byabout 90° in such a manner that the light ray bundle deflected by thesecond deflecting mirror 9 is preferably propagated parallel to thelight ray bundle 4 exiting from the lamp housing 1.

As an alternative to the carriage, there may also be provided a swiveldevice by which the deflecting mirror 8 may be swivelled from theposition shown in FIG. 1 into a position wherein the light ray bundle 4is no longer deflected, but is directed to the film stage 2.

For this mechanical movement of the deflecting mirror 8 into and out ofthe optical path of the light ray bundle 4, it is advantageous toprovide mechanically self-locking locking devices, by which thedeflecting mirror 8 is locked in the extended and in the retractedstate, respectively. This allows the drive system of the carriage or ofthe swivel device to be deenergized when the deflecting mirror 8 is inthe retracted or extended state. To this end, the locking devices mayfurther be provided with limit switches, which emit a signal when thedeflecting mirror 8 is in the desired retracted or extended state. Thisallows automatic switching using the deflecting unit 6.

The image generating module 7 is arranged such that the light ray bundledeflected by the second deflecting mirror 9 is incident on the imagegenerating module 7. As shown in FIG. 2, the image generating module 7comprises a light modulator 10 and projection optics 11. The lightmodulator 10 is controlled on the basis of predetermined image data insuch a manner that it generates an image which consists of image pixels,said image being projected by means of the projection optics 11.Further, there may also be provided a light integrator or a light mixingrod (not shown), which precedes the light modulator 10 and transformsthe light ray bundle 4 in such a manner that the light-modulating units21, 22, 23 described below are illuminated as uniformly as possible. Thelight modulator 10 comprises a color-splitting unit 12 having threemirrors 13, 14 and 15, which are arranged successively along a firstoptical axis, each of said mirrors being tilted at 45° relative to saidfirst optical axis. The mirror 13 disposed on the inlet side is a mirrorwhich only reflects the blue component of the white light of the lightray bundle. The remaining color components of the light pass through themirror 13 and are incident on the next mirror 14, which only reflectsthe green color component thereof. The red light component passingthrough this mirror 14 is then reflected by the mirror 15, whichselectively reflects red light.

The light modulator 10 further includes a color-combining unit 16comprising three mirrors 17, 18 and 19. Said mirrors 17, 18 and 19 arearranged along a second optical axis, which is parallel to the firstoptical axis of the light bundle incident on the light modulator 10.Further, these mirrors 17, 18 and 19 are tilted at 45° relative to thesecond optical axis and arranged such that the blue, green and red lightreflected by the mirrors 13, 14 and 15, respectively, is deflected so asto be propagated along the second optical axis. Thus, the blue, greenand red light ray bundles are combined to form one common light raybundle 20. Further, the light modulator 10 comprises threelight-modulating units 21, 22 and 23 (e.g. LCD modules), each modulatingone color component of the light split into blue, green and red colorcomponents, thus creating the required individual color pixels whosecombination yields the desired image. In the embodiment shown in FIG. 2,the light modulation unit 21 for the blue light component is arrangedbetween the mirrors 17 and 18. The light modulation unit 22 for thegreen light component is arranged between the mirrors 14 and 18, and thelight modulation unit 23 for the red light component is arranged betweenthe mirrors 14 and 15. The modulation using the light-modulating units21, 22 and 23 is carried out according to the digital and/or analog datapresent. The light ray bundle 20, which is color-modulated, is thenprojected onto the screen (not shown) by the projection optics 11. Themirrors 13, 14, 15 and 21, 22, 23 may be in the form of dichroicmirrors.

FIG. 3 shows a block diagram of the projection arrangement according tothe invention. As is evident from FIG. 3, the projection arrangementaccording to the invention comprises a projection unit 24 and a controlunit 25. The projection unit 24 includes the light modulator 10, theprojection optics 11, the lamp 26 arranged in the lamp housing 1, thedeflecting unit 6, the mechanical film stage 2 and the projection lens3. The film 5 is fed to the mechanical film stage 2. The control unit 25comprises a data input 27, a monitoring unit 28, a sound output 29, amemory 30, an operating unit 31, which includes an input unit, e.g. akeyboard, and a display device, e.g. a monitor, and further comprises anoutput interface (not shown), by which, e.g., the dimming of theauditorium lighting or the movement of a curtain away from theprojection surface may be controlled. The control unit 25 may beprovided as a separate unit, which may be set up separately from theprojection unit 24, e.g. in a different room.

Various data links may be used to transmit the data from the controlunit 25 to the projection unit 24. It is essential that the bandwidth besufficient for data transmission. For example, the LVDS system (LowVoltage Differential Signaling System, of the National Semiconductorcompany) or the PanelLink system of the Silicon Image company, whichallow transmission of large data volumes via a cable having only twowires, are advantageous.

The movie 32 consisting of stored image data is fed to the control unit25 via the data input 27. Said data input 27 may be, on the one hand, aninterface to an external network, e.g. the internet. On the other hand,said data input 27 may also be realized by a drive receiving a storagemedium, such as a DVD drive. The data entered via the data input 27 mayeither be written to the memory 30 by the monitoring unit 28 or useddirectly to control the light modulator 10 in the projection unit 24.Further, the monitoring unit 28 may also filter out sound data from theinput data and apply them to a theater sound system 33, synchronouslywith the image data, via the sound output 29. The control unit 25 mayalso be used to control the position of the first deflecting mirror 8(see FIG. 1), i.e. the first deflecting mirror 8 may be arranged eitherin the optical path between the lamp housing 1 and the mechanical filmstage 2, as shown in FIG. 1, or outside said optical path.

The monitoring unit 28 may further use the image data either unmodifiedto control the light modulator 10, or may perform an adjustment offormat or resolution or any other desired graphical transformation, saidadjustment or transformation being realizable both by hardware and bysoftware.

Further, the monitoring unit 28 allows to compensate distortions causedby the projection optics 11. These may be, for example, pin-cushion orbarrel distortions. To this end, the image data for controlling thelight modulator 10 are pre-distorted by the monitoring unit 28 in such amanner that said pre-distortion is compensated by the distortion causedby the projection optics 11, so that an image exhibiting as littledistortion as possible is projected on the screen 34. If desired, themonitoring unit 28 also allows to perform color adjustments and colorconversions.

The above-described data processing operations may be carried out eitherduring projection or may be performed in advance, with the processeddata then being stored in the memory 30.

Also, using the monitoring unit 28, an entire movie program may becomposed in advance via the operating unit 31. Thus, advertisements andtheatrical trailers preceding the actual movie may easily be compiled,and it is also possible, for example, to compile differentadvertisements for the children's program and for the evening program.Thus, the movie program for each screening may be compiled in advanceand then started by one single input via the operating unit 31. Sincethe control unit 25 may be set up in a different room than theprojection unit 24, it is possible, for example, to set up the controlunit 25 next to the person who is also selling the movie tickets. Thus,said person may sell the tickets as well as start and end the screeningof the movie.

Advantageously, the projection arrangement according to the inventionmay also comprise a camera (not shown), which is installed in theauditorium and records the image projected onto the screen 34 andtransmits it to the control unit 25, which displays the transmittedimage on the monitor of the operating unit 31. This allows to monitorthat the screening of the movie is effected correctly and, if necessary,to take action immediately.

If a movie is to be projected using the image generating module 7, thismay be entered via the operating unit 31 of the projection arrangementaccording to the invention. Thereupon, the monitoring unit 28 will firstcheck whether the first deflecting mirror 8 is in the position shown inFIG. 1. Should it not be in said position, the swivel device will becontrolled such that the first deflecting mirror 8 is swivelled to theposition shown in FIG. 1. Then, the screening of the selected movie,including the advertisements and theatrical trailers optionallydetermined in advance for said film, is automatically started. If aconventional positive film is to be screened, this may be entered viathe operating unit 31. The monitoring unit 28 will then check whetherthe first deflecting mirror 8 is in the position shown in FIG. 1. If itis in said position, the monitoring unit 28 will control the swiveldevice such that the first deflecting mirror 8 is swivelled out of theoptical path between the lamp housing 1 and the mechanical film stage 2.Then, the screening of the positive film including the soundtransmission is effected in the conventional manner.

The projection arrangement according to the invention may also beemployed such that, during the projection of a movie using the imagegenerating module 7, switching may be effected to the projection of saidmovie using the transillumination method. This is advantageous, forexample, if problems occur during the projection using the imagegenerating module 7. In order to realize this, the movie must be presentboth as a conventional positive film and in the form of image data forthe image generating module 7. Further, to this end, the projectionarrangement must be configured such that the deflecting unit 6 deflectsthe light ray bundle 4 between the lamp housing 1 and the mechanicalfilm stage 2. Moreover, the monitoring unit 28 is provided such that itmonitors the projection using the image generating module 7 by simplesensory equipment or by a control software, which controls, for example,the data flow from the memory 30 or the data input 27. Now, theprojection is controlled such that, during the projection using theimage generating module 7, the positive film also runs synchronously orwith a slight delay. If the monitoring unit 28, now, detects problemsoccurring during the projection using the image generating module 7, theoptical path switch 6 is directly controlled so that now the positivefilm can be projected. If both movies are running synchronously, it iseven possible to use either the sound or only the image of the positivefilm, so that the other information is present in high, preferablydigital, quality, during a limited failure of the system.

The image generating module 7, the deflecting unit 6 and the projectionoptics 11 may be provided as a projection module which can be coupled toand uncoupled from a conventional projector, such as that shown, forexample, in FIG. 14. Being provided as a separate, portable projectionmodule, this projection module may be coupled, for example, to theprojector as required. It is also possible to acquire such a projectionmodule for several projectors and to couple the projection module to thedesired projector in each case.

In order to allow easy coupling of the projection module to saidconventional projectors, there is preferably provided a support, whichconsists of a first coupling device provided on the respective projectorand a second coupling device provided on the projection module. Thefirst coupling device is disposed in a defined spatial relationship tothe conventional projector. Preferably, it is attached to the foot ofthe lamp housing 1 of the projector and comprises a base having aself-centering three-point support, on which the projection module maybe placed. The self-centering three-point support comprises, forexample, three conical sleeves, in which corresponding counterparts ofthe projection module engage when the projection module is restedthereon. Said conical sleeves may be individually adjusted in theirposition perpendicular to the plane of the supporting surface and may beadjusted together in the plane of the supporting surface. Thus, thesupport has a means of adjustment, which is provided in the firstcoupling device remaining on the projector so that the projection modulemerely needs to be placed on the three-point support and is thenimmediately ready for operation.

Advantageously, the support may further comprise a data and currentinterface, which comprises a first plug element provided on the firstcoupling device and a second plug element provided on the secondcoupling device. Said plug elements are arranged such that, when theprojection module is placed on the three-point support, a mechanical andelectrical contact is established. To this end, one of said plugelements may be floatingly mounted, while the other of said plugelements has a fixed position.

If the support, as described above, is provided with a data interface, acorresponding supply line is provided for each conventional projector.This allows to provide just one single control unit 25 for all of theconventional projectors, so that the projection module and the controlunit 25 are provided as separate units. On the one hand, this increasesthe transportability of the projection module. On the other hand, thecontrol unit may be arranged at any desired location, so that there isno interference with the space in the projection booth in which theconventional projector is located.

Alternatively, the projection module may comprise the control unit 25.In this case, the projection module is an operable, transportable unit.

FIGS. 4 and 5 show an alternative embodiment of the light modulator 10.In this embodiment, three prisms 35, 36 and 37 are arranged and providedsuch that, in the first prism 35, blue light from the light ray bundledeflected by the second deflecting mirror 9 is filtered out byreflection and directed to a tilting mirror matrix 38. Of the remaininglight bundle, only the red light is filtered out by reflection in thesecond prism 36 and directed to a tilting mirror matrix 39. Theremaining light, namely the green component, is directed to a tiltingmirror matrix 40 by a third prism 37. The individual color componentsare suitably modulated and reflected back by the tilting mirror matrices38, 39 and 40 according to the image data so that they are combined toform one common light ray bundle 20, which is projected onto the screenvia the projection optics 11. FIG. 5 schematically shows that theindividual mirrors may be tilted such that the imaging light isreflected back to the projection optics (solid line) or reflected backonto a diaphragm element 41 (doffed line). If the light is reflectedonto the diaphragm element 41, the corresponding color pixel remainsdark in the represented image. Instead of the tilting mirror matrices38, 39 and 40, reflective LCD modules may be used as well.

The deflecting unit 6 may also be configured such that a rotatablemirror is provided, which deflects the light bundle 4 to the imagegenerating module 7 in a first position, and deflects the light bundle 4to the mechanical film stage 2 in a second position.

In the following, alternative embodiments of the deflecting unit 6 willbe described with reference to FIGS. 6 to 11, each of them showingenlarged, schematic views of an uncoupling location, which is situatedin the optical path between the lamp housing 1 and the projection lens3. Thus, instead of the first deflecting mirror 8 of the deflecting unit6 (FIG. 1), a rotatable mirror 42 may be arranged at a position in theoptical path of the light bundle 4, said mirror deflecting the lightbundle 4 in a first position (FIG. 6) and being arranged in the lightbundle 4 in a second position (FIG. 7) such that only minimal shadingoccurs in the light bundle 4. Said shading decreases as the thickness ofthe mirror decreases.

Alternatively, as the deflecting element, a prism 43 (FIG. 8) may alsobe used, which may be moved into the optical path of the light bundle 4,for example by a controllable carriage (not shown), such that adeflection is effected by total reflection in the prism. In a secondposition of the prism 43, the prism is moved out of the optical path ofthe light bundle 4, so that no deflection occurs, and the light isincident on the film held on the film stage 2.

The deflecting unit 6 may also be realized by an optical waveguide 44(which may be either flexible or rigid), whose end portion 45 is movableinto the optical path of the light bundle 4 for uncoupling (FIG. 9). Theoptical waveguide 44 may be used simultaneously as a light integratorfor the image generating module, so that, at the end of the opticalwaveguide 44 facing the image generating module 7, an image field ispresent, which is as uniformly illuminated as possible and adapted tothe light modulators. The optical waveguide 44 may be provided such thatthere is a change in cross-section between the beam cross-sectionincident on the optical waveguide and the beam cross-section exitingtherefrom.

The deflecting unit 6 may also comprise a beam-splitting mirror 46,which splits the light bundle 4 into two light bundles 47, 48 extendingorthogonally to each other, and shutters or diaphragms 49, 50, by whichone each of said split light bundles 47, 48 is shaded. Thebeam-splitting mirror 46 is indicated by a broken line in FIGS. 10 and11. In the condition shown in FIG. 10, the light bundle 47 is shaded,while in the condition shown in FIG. 11, the light bundle 48 is shaded.The shutters 49, 50 may be moved, e.g. magnetically orpiezomechanically, in order to selectively shade the light bundles 47,48. The beam-splitting using said mirror may also be realized by abeam-splitting prism.

The deflecting unit 6 may also be realized by electronically switchableelements, so that no mechanical movement of components for switching theoptical path is required. In this embodiment, for example, the lightbundle 4 is polarized. This may be realized either by a light source,which emits polarized light, or by a polarizer, through which anon-polarized light bundle passes. The light bundle polarized in thismanner then passes through an electronically controllable element usingwhich the polarization direction of the light bundle may be rotated.Such an element may be, for example, an LCD module or a Faradaymodulator. Arranged following said element is a polarizing beam-splittercube, which allows an incident light ray bundle to pass or deflects itas a function of its polarization. Thus, the deflection of the light raybundle 4 may be controlled electronically via the control of the elementby which the polarization direction can be rotated.

As has already been described, the deflecting unit 6 may be arrangedbetween the light source 1 and the film stage 2 or between the filmstage 2 and the projection lens 3.

Further, it is also possible to arrange the lamp housing 1 displaceablyso that the light bundle 4 arrives at the film stage 2 in a firstposition of the lamp housing 1 and arrives at the image generatingmodule 7 in a second position of the lamp housing 1. Preferably, saiddisplacement is effected transversely to the direction in which thelight bundle 4 exits. Alternatively, the lamp housing may be fixed, andthe mechanical film stage 2 and the image generating module 7 may bearranged to be displaced together in such a manner that the light bundle4 is directed to the film stage 2 in a first position of the film stage2 and of the image generating module 7, and that the light bundle 4 isdirected to the image generating module 7 in a second position of thefilm stage 2 and of the image generating module 7. In a furtherembodiment, it is possible to move the image generating module 7 into anoptical path extending from the light source 26 to the projectionsurface 34 via the film stage 2. In this case, the image generatingmodule 7 may preferably be realized by a transmission LCD module.

In a further embodiment of the invention, the projection optics 11 ofthe image generating module 7 are provided such that an intermediateimage of the modulated image is generated in such a manner that theprojection lens 3 may be used for both projection of the positive filmand projection using the image generating module 7.

As the light modulator 10, a GLV module 51 may also be employed. FIGS.12 and 13 schematically show the operation of such GLV module 51 (aswitchable diffracting reflection grating), which may be employed, forexample, in the light modulator shown in FIGS. 4 and 5 instead of thetilting mirror matrices 38, 39, 40 used therein. The GLV module 51comprises several parallel reflecting strips 52 for each image pixelwhich are alternatingly fixed in their position and positioned moveablein height. In a first adjustable position of the strips 52, all of saidstrips 52 are situated in one plane, so that the light incident on thestrips 52 via a deflecting element 53 is reflected back (FIG. 12). In asecond position of the strips 52, shown in FIG. 13, every other strip 52is offset in height relative to the other strips 52 so that the strips52 form a reflecting diffraction grating. Due to said diffraction, alarge part of the incident light is not reflected back again to thedeflecting mirror 53. Thus, the intensity of the light reflected back bythe deflecting mirror 52 is substantially lower than in FIG. 12. Thisallows to realize brightness/darkness control of the image pixel. Thus,it is essential for this GLV module 51 that the angle of the lightreflected by this module be modifiable as described above and that,depending on said angle, the reflected light be used either to generatea bright image pixel or be directed to a beam trap and thus darkened. Itdepends essentially on the construction of the light modulator whetherthe reflected light (FIG. 12) or the diffracted light (FIG. 13) is usedfor a brightened image pixel. The GLV module 51 may be present as amatrix arrangement so that the image pixels are arranged in lines andcolumns. Alternatively, the GLV module 51 may be realized as a lineararrangement of image points. In this case, scanning of the image line orimage column is then required for imaging. This may be realized by knownscanning devices arranged following the light modulator 10.

Referring to FIG. 15 an attachable module 100 includes light modulator10, optical device 11 and control device 6. Control device 6 may includea moving device 102 whereby light source 104 is moveable between twopositions. In a first position, light source 104 is incident on lightmodulator 10. In a second position, light source 104 is incident onlight modulator 10. In a second position, light source 104 is incidenton the film stage 2. This arrangement is depicted in FIG. 18.

In another embodiment of the invention, as shown in FIG. 17 controldevice 6 includes a moving device 106 that also connects light modulator10 to film stage 2. Referring to FIG. 17, moving device 106 shifts lightmodulator 10 and film stage 2 as a unit between a first position inwhich light from the light source 104 is incident on the light modulatorto a second position in which light from light source 104 is incident onthe film stage 2.

Referring to FIG. 16, the invention may also be practiced as asupplementary module 108. Referring to FIG. 19, in this embodiment, afirst coupling member 110 is secured to the lamp housing one of theprojector. A second coupling member 112 is secured to the supplementarymodule 108. The supplementary module includes second coupling member112, control device 6, light modulator 10 and optical device 11.Desirably optical device 11 is some form of projection optics forprojecting the image created by light modulator 10.

Referring again to FIG. 10, another embodiment of the invention mayinclude an image recording device 114. Image recording 114 typicallyincludes a video camera or other image recording device that would allowmonitoring of the projected image by a person in a location remote fromthe auditorium or other area in which the projected image is beingdisplayed.

What is claimed is:
 1. A projection arrangement for projecting an imageonto a projection surface, said arrangement comprising a light source, acontrol unit, a selectably attachable module, the attachable modulecomprising a light modulator, which is controllable by said control unitin order to generate an image on the basis of predetermined image data,an optical projection device, arranged following said light modulator,for projecting said image onto the projection surface and a controldevice, the projection arrangement further comprising a film stage forholding a sequential series of positive images recorded on a carriermedium, projection optics, arranged following the film stage whenprojecting the positive images, and wherein the control device, allowslight to either be directed from the light source to the light modulatoror to illuminate the positive images, which are held by the film stage,and wherein the projection arrangement is adapted to project movingimages from both the carrier medium and the light modulator.
 2. Theprojection arrangement as claimed in claim 1, wherein the control devicecomprises an optical deflecting device, which is movable into theoptical path between the light source and the film stage or between thefilm stage and the projection optics, in order to direct the light fromthe light source to the light modulator.
 3. The projection arrangementas claimed in claim 1, wherein the light modulator is movable into anoptical path extending from the light source via the film stage to theprojection surface.
 4. The projection arrangement as claimed in claim 1,wherein the control device comprises an optical path switch arranged inthe optical path between the light source and the film stage, in orderto direct the light from the light source either to the film stage or tothe light modulator.
 5. The projection arrangement as claimed in claim1, wherein the control device comprises an optical path switch, which isarranged following the film stage and directs the light either to thelight modulator or to the projection optics.
 6. The projectionarrangement as claimed in claim 4, wherein the optical path switchcomprises a partially reflective mirror, which splits the light from thelight source into two partial beams, and a diaphragm element, by whichone of said partial beams may be selectively shaded.
 7. The projectionarrangement as claimed in claim 5, wherein the optical path switchcomprises a partially reflective mirror, which splits the light from thelight source into two partial beams, and a diaphragm element, by whichone of said partial beams may be selectively shaded.
 8. The projectionarrangement as claimed in claim 1, wherein the control device comprisesa moving device by which the light source is movable from a firstposition, in which the light is incident on the light modulator, to asecond position, in which the light is incident on the film stage. 9.The projection arrangement as claimed in claim 1, wherein the controldevice comprises a moving device by which the light modulator is movabletogether with the film stage from a first position, in which the lightis incident on the light modulator, to a second position, in which thelight is incident on the film stage.
 10. The projection arrangement asclaimed in claim 1, wherein a splitting device is provided, which splitsthe light from the light source into different color components, and thelight modulator comprises several light-modulating units, each of whichmodulates one of said color components.
 11. The projection arrangementas claimed in claim 10, wherein a combining device is provided whichcombines the light emitted by the light-modulating units to form onesingle light bundle and guides said light bundle to the optical device.12. The projection arrangement as claimed in claim 1, wherein the lightmodulator comprises an LCD module, a tilting mirror matrix or a GLVmodule.
 13. The projection arrangement as claimed in claim 1, whereinthe projection optics and the optical device are realized as one singleprojection unit.
 14. The projection arrangement as claimed in claim 1,wherein a memory for storing data and an input interface for receivingdata as well as an output interface are provided.
 15. The projectionarrangement as claimed in claim 14, wherein a sound unit is providedwhich can extract sound data from said data and feed them into a soundsystem via the output interface.
 16. The projection arrangement asclaimed in claim 1, wherein a display device and an image recordingdevice are provided, said image recording device being able to recordthe image projected onto the projection surface and to represent it onthe display device.
 17. A projection arrangement for projecting movingimages onto a projection surface, which arrangement comprises severalprojection units, each comprising a light source; a film stage, arrangedfollowing said light source, for holding a sequential series of positiveimages recorded on a carrier medium; projection optics, arrangedfollowing the film stage when projecting the positive images; and afirst coupling member; said projection arrangement further comprising acontrol unit; a supplementary module comprising a light modulator whichis controllable by the control unit in order to generate an image on thebasis of predetermined image data; an optical device, arranged followingthe light modulator, for projecting said image onto the projectionsurface; and a second coupling member cooperating with said firstcoupling member, wherein the supplementary module may be coupled to theprojection units via said coupling members, and wherein saidsupplementary module further comprises a control device, allowing lightto either be directed from the light source of the projection unit, towhich the supplementary module is coupled, to the light modulator or toilluminate the sequential series of positive images, which are held bythe film stage, with said light.
 18. A supplementary module for use in amotion picture projection arrangement, the supplementary modulecomprising a control unit, a light modulator, which is controllable bysaid control unit in order to generate an image on the basis ofpredetermined image data, an optical device, arranged following thelight modulator, for projecting said image onto a projection surface,and a control device, which device, when the supplementary module is ina condition coupled to a projector comprising a light source and a filmstage, arranged following said light source, for holding a sequentialseries of positive images recorded on a carrier medium, allows lighteither to be directed from the light source to the light modulator or toilluminate a positive image, which is held by the film stage, with saidlight.
 19. A supplementary module for use in cooperation with severalmotion picture projection arrangements, the supplementary modulecomprising a control unit, a light modulator, which is controllable bysaid control unit in order to generate an image on the basis ofpredetermined image data, an optical device, arranged following thelight modulator, for projecting said image onto a projection surface,and a control device, which device, when the supplementary module is ina condition coupled to a projector comprising a light source and a filmstage, arranged following said light source, for holding a positiveimage recorded on a carrier medium, allows light to be directed from thelight source to the light modulator or to illuminate a positive image,which is held by the film stage, with said light.